Camera module having MEMS actuator, connecting method for shutter coil of camera module and camera module manufactured by the same method

ABSTRACT

Disclosed is a camera module including a substrate which is provided with an electrode pad and an image sensor; a housing which is stacked on the substrate and of which an upper portion is opened so that light is incident to the image sensor; a MEMS actuator which is installed at the housing and has an electrode terminal at one side thereof, and a conductive pattern which is formed at the housing, wherein a lower end of the conductive pattern is connected with the electrode pad of the substrate, and an upper end thereof is connected with the electrode terminal of the MEMS actuator, whereby it is possible to improve electrical reliability between the electrode terminal of the MEMS actuator and the electrode pad of the substrate and facilely form the electrical connection therebetween, thereby reducing the number of processes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of co-pending U.S. application Ser.No. 13/698,218 filed on Nov. 15, 2012, which is the National Phase ofPCI International Application No. PCT/KR2011/003728 filed on May 20,2011, which claims priority to Patent Application No. 10-2010-0047444filed in the Republic of Korea on May 20, 2010, and Patent ApplicationNo 10-2010-0098431 filed in the Republic of Korea on Oct. 8, 2010. Theentire content of all of the above applications are hereby expresslyincorporated by reference.

TECHNICAL FIELD

The present invention relates to a camera module, and particularly to acamera module which can facilely form an electrical connection betweenan MEMS (Micro Electro Mechanical Systems) actuator and an electrode padof a substrate, a connecting method for a shutter coil of the cameramodule, which can easily form a connection between the shutter coil andan output terminal pad of a PCB (Printed Circuit Board) through welding,and a camera module manufactured by using the same method.

BACKGROUND ART

Generally, a compact camera module is being applied to various ITequipment and mobile communication devices such as a camera phone, a PDAand a smart phone.

The camera module includes an image sensor such as CCD and CMOS as amain component, and it is so manufactured as to be capable of adjustingfocus, thereby controlling an image size.

Herein, the camera module includes a plurality of lenses, and each lensis movably arranged so that a relative distance can be changed tocontrol a focal distance.

Recently, a study on realizing auto-focus using an MEMS actuator insteadof an existing VCM (Voice Coil Motor) has been actively carried out.

In the MEMS actuator, a moving lens is fixed to a silicon wafer insteadof the existing VCM. Therefore, when a voltage is applied, a portion towhich the moving lens is fixed is move up and down by electrostaticforce to minutely adjust the moving lens, thereby performing anauto-focusing function.

As shown in FIG. 1, an electrode terminal 11 of the MEMS actuator 10 andan electrode pad 21 of a substrate are soldered with an FPCB (FlexiblePrint Circuit Board) 30 so as to be electrically connected with eachother.

However, in the MEMS actuator, since the electrode terminal isstructurally formed at a lower surface the problems are that it takesmuch time to solder the PCB to the electrode terminal and also troublesoccurs frequently after the electrical connection.

Further, the camera module may be defective due to high temperature andthermal shock during the soldering.

Meanwhile, a camera has a shutter which functions to control time fortransferring light through a lens to an image sensor. The shutter isopened only for a predetermined time period to allow light to pass andthen closed after the predetermined time period to block out the light.The shutter takes the shape of a coil to obtain magnetic field andelectromagnetic force for driving the shutter.

In order to connect a coil wire terminal of the shutter and positive andnegative pads of a substrate which can perform a command of a driver IC,a manual soldering method and a method of coating and hardeningconductive Ag-epoxy resin are main used. However, these methods havesome problems in workability and productivity, and also any connectionmethod applied to a very small space such as a camera module always hasvarious problems.

There are some representative problems in that a terminal of snubbercircuit of the sensitive MEMS actuator is weak in heat, flux gas of leadgenerated upon soldering has bad influence on an image sensor and an IRfilter, thereby deteriorating an image quality, and a short-circuit withrespect to a peripheral terminal such as a grounding portion may begenerated, thereby causing a trouble in the operation of the shutter.

DISCLOSURE Technical Problem

An object of the present invention is to provide a camera module whichcan facilely form an electrical connection between an electrode terminalof an MEMS actuator and an electrode pad of a substrate,

Further, another object of the present invention is to a camera modulein which a shutter coil is connected with an output terminal pad bywelding, thereby protecting other components of the camera module fromheat and also preventing performance deterioration of an image sensorand the like.

Technical Solution

To achieve the object of the present invention, the present inventionprovides a camera module including a substrate which is provided with anelectrode pad and an image sensor; a housing Which is stacked on thesubstrate and of which an upper portion is opened so that light isincident to the image sensor; a MEMS actuator which is installed at thehousing and has an electrode terminal at one side thereof, and aconductive pattern which is formed at the housing, wherein a lower endof the conductive pattern is connected with the electrode pad of thesubstrate, and an upper end thereof is connected with the electrodeterminal of the MEMS actuator.

Preferably, a lower end of the conductive pattern is exposed through abottom surface of the housing so as to be connected with the electrodepad of the substrate, and an upper end of the conductive pattern isexposed through an upper surface of the housing so as to be connectedwith the electrode terminal of the MEMS actuator.

Preferably, the electrode pad of the substrate comprises a plurality ofpositive terminals and negative terminals, and a lower end of theconductive pattern is connected with the plurality of positive terminalsand negative terminals.

Preferably, the housing includes a holder which forms a light runningspace through light is incident to the image sensor, and a lens barrelwhich is inserted into the light running space of the holder and formedwith a hole so as to fix one or more lenses.

Preferably, the conductive pattern includes a first conductive patternand a second conductive pattern, and the first conductive pattern isformed to be extended from the electrode pad to an inner surface of thelight running space of the holder, and the second conductive pattern isformed at an outer surface of the lens barrel so as to be contacted withthe first conductive pattern and also to be extended to an uppersurface.

Preferably, an extended portion is formed at an upper end of the lensbarrel so as to be contacted with the electrode terminal of the MEMSactuator, and the second conductive pattern is extended to an uppersurface of the extended portion.

Further, the present invention provides a shutter coil connection methodof the camera module, which has a shutter and a MEMS actuator forperforming auto-focus, including welding a shutter coil extended fromthe shutter to an output terminal pad formed at a PCB so as to transfera control signal of the shutter.

Preferably, wherein the shutter coil and the output terminal pad arerespectively provided in a pair so as to be corresponding to a positivepole and a negative pole.

Preferably, the shutter coil is welded by a welding machine.

Preferably, the shutter coil has a diameter of 0.04˜0.06 mm, and avoltage at a welding tip of the welding machine is 1.2˜1.4V, and weldingtime of the welding machine is 5˜9 ms.

Advantageous Effects

According to the present invention as described above, it is possible toimprove electrical reliability between the electrode terminal of theMEMS actuator and the electrode pad of the substrate and facilely formthe electrical connection therebetween, thereby reducing the number ofprocesses.

Further, it is additionally possible to form the connection without thePCB, thereby enhancing price competitiveness.

Furthermore, according to one embodiment of the present invention, sincethe shutter coil is connected with the output terminal pad by welding,it is possible to protect other components of the camera module fromheat and also prevent the performance deterioration of the image sensorand the like.

DESCRIPTION OF DRAWINGS

*28 The above and other objects, features and advantages of the presentinvention will become apparent from the following description ofpreferred embodiments given in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view of a conventional camera module.

FIG. 2 is an exploded perspective view of a camera module according toan embodiment of the present invention.

FIG. 3a is a plan view of camera module housing according to theembodiment of the present invention.

FIG. 3b is a side view of the camera module housing according to theembodiment of the present invention.

FIG. 3c is a bottom view of the camera module housing according to theembodiment of the present invention.

FIG. 4 is a perspective view of a lens barrel of the camera moduleaccording to the embodiment of the present invention.

FIG. 5 is an enlarged view of the lens barrel according to theembodiment of the present invention.

FIG. 6 is an exploded perspective view of a camera module according toanother embodiment of the present invention.

FIG. 7 is an exploded perspective view of the camera module including anMEMS actuator and a shutter.

FIG. 8 is a flow chart showing a connection method of a shutter coil ofthe camera module according to an embodiment of the present invention.

FIGS. 9 to 12 are photographs showing a connecting process in theconnection method of a shutter coil of the camera module according tothe embodiment of the present invention.

BEST MODE

Hereinafter, the embodiments of the present invention will be describedin detail with reference to accompanying drawings. However, the presentinvention is not limited to the embodiments, and it should be understoodthat the present invention comprises all of equivalents and substitutesincluded in the technical scope and spirit of the invention.

It is to be noted that, in this specification, the expression that “acertain construction element is connected to another constructionelement” means that the certain construction element is directlyconnected to the construction element, and also means that a thirdconstruction element may be interposed therebetween.

On the other hand, the expression that “the certain construction elementis directly connected to the construction element” means that the thirdconstruction element is not interposed therebetween.

The terms used herein are merely to describe a specific embodiment, andthus the present invention is not limited to them. Further, as far assingular expression clearly denotes a different meaning in context, itincludes plural expression.

It is understood that terms “comprises”, “comprising”, “includes” or“has” intend to indicate the existence of features, numerals, steps,operations, elements and components described in the specification orthe existence of the combination of these, and do not exclude theexistence of one or more other features, numerals, steps, operations,elements and components or the existence of the combination of these oradditional possibility beforehand.

Also, it is understood that accompanying drawings are enlarged orreduced for the convenience of explanation.

The same reference numerals are given to the same or correspondingparts, and the description thereof will not be repeated.

Referring to FIG. 2, the camera module according to an embodiment of thepresent invention includes a substrate 100 in which an electrode pad 110and an image sensor 120 are formed, an housing 200, 300 which is stackedon the substrate 100 and of which an upper portion is opened so thatlight is incident to the image sensor 120, an MEMs actuator 400 which isinstalled at the housing 200, 300 and has an electrode terminal 420 atone side thereof, and a conductive pattern which is formed at thehousing 200, 300. A lower end of the conductive pattern is connectedwith the electrode pad 110, and an upper end thereof is connected withthe electrode terminal 420 of the MEMS actuator 400.

The conductive pattern can be formed by all general methods of forming aconductive material, and also can be patterned at the same time ofinjection molding of the housing.

A general PCB can be used as the substrate 100. At an upper surface ofthe substrate 100, there is formed an electric wiring.

In the electrode pad 110 of the substrate 100, a positive terminal 111and a negative terminal 112 are formed at a side surface of thesubstrate 100, and also another positive terminal 111 a and anothernegative terminal 112 a may be formed at an opposite side surfacethereof.

The image sensor 120 may include a pixel area (not shown) having aplurality of pixels, and a plurality of electrodes (not shown). Herein,the pluralities of electrodes are electrically connected with electrodes(not shown) of the substrate 100 by using a wire bonding equipment.

The housing 200, 300 may have any structure, if it can be stacked on thesubstrate 100, and its upper portion is opened so that light is incidentto the image sensor 120, and the MEMS actuator 400 can be fixed thereon.

In the camera module according to the embodiment of the presentinvention, the housing has a structure that a holder 200 and a lensbarrel 300 are coupled with each other.

The holder 200 is formed at the substrate 100 so as to form a lightmiming space 211 which is opened so that light is incident to the imagesensor 120.

More detailed, an upper portion of the light running space 211 may beformed into a cylindrical opening so as to receive the lens barrel 300,and a lower portion thereof may be formed into a square opening so thatlight is incident to the image sensor 120. Therefore, an upper portion210 of the holder 200 is formed into a cylindrical shape, and a lowerportion 220 thereof is formed into a square shape.

However, the holder 200 may have any structure or shape, if it can formthe light running space 211.

A first conductive pattern 231, 232 is formed at an inner side surfaceof the light running space 211. The first conductive pattern 231, 232will be described in detail with reference to FIGS. 3a to 3 c.

As shown in FIGS. 3a and 3b , the first conductive pattern 231, 232 isformed at the inner side surface of the light running space 211 so as tohave a desired thickness and width. Further as shown in FIG. 3c , thefirst conductive pattern 231, 232 is exposed through a side surface of abottom surface 221 of the holder 200 so as to be electrically connectedwith the electrode pad 110 when the holder 200 is stacked on thesubstrate 100 of FIG. 2.

Herein, the first conductive pattern 231, 232 exposed through the bottomsurface 221 of the holder 200 is bonded so as to be electricallyconnected by using a conductive adhesive such as Ag-epoxy.

In case that the electrode pad 110 of the substrate 100 is provided inplural number 111 a, 112 a, another conductive pattern 231 a, 232 awhich is not described is electrically connected with them.

The lens barrel 300 is disposed at the upper portion of the holder 200,and a circular hole 232 is formed at a center portion of the lens barrel300 so as to open the lens barrel 300 up and down. A fixed lens (notshown) is inserted into the circular hole 232, and a second conductivepattern 330, 340 is formed at an outer surface of the lens barrel 300.

The lens barrel 300 has a desired size and shape which can be insertedinto the light running space 211.

Referring to FIGS. 4 and 5, the second conductive pattern 330, 340includes a lower end 332, 342, an upper end 334, 344, and a connectionwire 331, 341 which electrically connects the lower end 332, 342 and theupper end 334, 344.

The lower end 332, 342 of the second conductive pattern 330, 340 isformed at an outer surface of the lower end 310 of the lens barrel 300in a height direction thereof so as to be electrically connected withthe first conductive pattern 231, 232 of the holder 200 by contactingeach other.

Another lower end 333, 343 of the second conductive pattern 330, 340 maybe additionally formed according to the number of the electrode pads 110formed at the substrate 100. If one of the conductive patterns isdefective, the electrical connection can be maintained by using otherconductive patterns, thereby increasing electrical reliability thereof.

Hereinafter, construction of forming the electric connection between thelens barrel 300 and the electrode terminal 420 of the MEMS actuator 400will be described.

An upper portion 320 of the lens barrel 300 is formed into a plateshape, and protrusions 321 are formed at a side surface thereof so as tofix the MEMS actuator 400. One of the protrusions 321 is protrudedupward in a desired height so as to form an extended portion 322. Asshown in FIG. 4, the upper end 334, 344 of the second conductive pattern330, 340 is formed at an upper surface 322 a of the extended portion322,

The extended portion 322 has a desired height which can be contactedwith the electrode terminal 420 of the MEMS actuator 400 when the MEMSactuator 400 is installed at the lens barrel 300.

The MEMS actuator minutely adjusts a moving lens (not Shown) using asilicon wafer instead of an existing voice coil, and the electrodeterminal 420 is formed at an upper surface thereof.

An opening 412 is formed at a center portion of the MEMS actuator 400.Although not shown in the drawings, a lens mount pad (not shown) forsupporting the moving lens (not shown) is formed at a side surface ofthe opening 412. The lens mount pad is driven up and down byelectrostatic force so as to adjust focus of the moving lens.

The electrode terminal 420 of the MEMS actuator 400 includes a positiveelectrode 421 and a negative electrode 422 which are electricallyconnected by being contacted with. Herein, in order to secure theelectrical reliability, the electrode terminal 420 and the upper end334, 344 of the second conductive pattern 330, 340 may be fixed to eachother using a conductive adhesive.

Herein, in order to prevent an electrical short with adjacentelectrodes, the conductive adhesive is an anisotropic conductiveadhesive.

By such a construction, the electrode pad 110 of the substrate 100 andthe electrode terminal 420 of the MEMS actuator 400 are connected withother through the first and second conductive patterns 231, 232, 330,340 so as to be electrically connected at the same time of assemblingthe camera module, thereby simplifying a manufacturing process thereof.

FIG. 6 shows an exploded perspective view of a camera module accordingto another embodiment of the present invention.

Since a construction of the camera module of the embodiment is the sameas that of the previous embodiment, detailed description thereof will beomitted.

In the camera module of the embodiment of the present invention, thepositive terminal 111 and the negative terminal of the electrode pad 110are formed at one side of the substrate 100 so as to be electricallyconnected with the first conductive pattern 231, 232.

Further, the first conductive pattern 231, 232 is electrically connectedwith the second conductive pattern 330, 340 of the lens barrel 300, andthe second conductive pattern 330, 340 is connected with the electrodeterminal 410 of the MEMS actuator 400.

By such a construction, the electrode pad 110 formed at the substrate100 can be facilely connected with the electrode terminal 420 of theMEMS actuator 400. Particularly, the electrode pad 110 does not need tochange its existing position, and an extra manufacturing cost is notneeded.

FIG. 7 is an exploded perspective view of the camera module including anMEMS actuator and a shutter. As shown in FIG. 7, the camera modulemanufactured by a shutter coil connection method according to thepresent invention includes an MEMS actuator 20 and a shutter 30 in orderto reduce its weight and size. The camera module may include anelectromagnetic shielding box 10, an image sensor 40 and a PCB 50.

In the MEMS actuator 20, a comb driver functions to adjust the focususing electrostatic force and the shutter 30 is operated at apredetermined speed by magnetic field and electromagnetic force based ona shutter coil wound on a magnetic body. The image sensor 40 functionsto receive an optical signal from an outside and convert it into anelectric signal, and the PCB 50 is a ceramic substrate on which acircuit for transferring various electric signals is printed. The imagesensor 40, the electromagnetic shielding box 10 and the like are may bemounted on an upper pad of the PCB 50.

In case of the camera module manufactured by the shutter coil connectionmethod according to the present invention, since it has a small size, ifeach element is mounted on the PCB 50, a connection space of the shuttercoil 32, 34 becomes very narrow. Particularly, in case of welding, itmay exert a bad influence on other elements.

FIG. 8 is a flow chart showing a connection method of a shutter coil ofthe camera module according to an embodiment of the present invention.Referring to FIG. 8, in the shutter coil connection method of the cameramodule according to the present invention, the shutter coil 32, 34extended from the shutter 30 is welded to an output terminal pad 52, 54formed at the PCB 50 in order to transfer a control signal of theshutter 30 (S10).

Herein, the shutter coil 32, 34 is a wire which is extended from thecoil wound on the magnetic body of the shutter 30 to an outside. Theshutter coil 32, 34 is formed of copper. Further, the output terminalpad 52, 54 of the PCB 50 is provided in a pair so as to be welded withthe shutter coil 32, 34 having a positive pole and a negative pole. Theoutput terminal pad 52, 54 is formed by gold-plating on a copper foil.

In the welding process, the shutter coil 32, 34 is welded by a weldingmachine W. In case that the shutter coil 32, 34 has a diameter of0.04˜0.06 mm, it is preferable that a voltage at a welding tip of thewelding machine W is 1.2˜1.4V and welding time of the welding machine Wis 5˜9 ms. In this case, since heat is generated locally, the heat doesnot have any influence on other elements (e.g., the image sensor or theMEMS actuator).

FIGS. 9 to 12 are photographs showing a connecting process in theconnection method of a shutter coil of the camera module according tothe embodiment of the present invention. As shown in FIGS. 9 to 11, eachshutter coil 32, 34 is welded to the output terminal pad 52, 54 so as tobe corresponding to a positive pole and a negative pole suing thewelding machine W. Herein, the output terminal pad 52, 54 and theshutter coil 32, 34 are directly coupled with each other using the heatwhich is locally generated at a contacted point therebetween by apotential difference of the welding tip without a solder,

Finally, as shown in FIG. 12, since the connection is not achieved by asolder, it is not necessary to provide a space for other material (e.g.,solder, Ag-epoxy), and also it is facile to mount the electromagneticshielding box 10.

Although various embodiments are provided herein in order to explain theprinciples, the present invention is not limited to these embodiments.

INDUSTRIAL APPLICABILITY

According to the present invention as described above, it is possible toimprove electrical reliability between the electrode terminal of theMEMS actuator and the electrode pad of the substrate and facilely formthe electrical connection therebetween, thereby reducing the number ofprocesses.

Further, it is additionally possible to form the connection without thePCB, thereby enhancing price competitiveness.

Furthermore, according to one embodiment of the present invention, sincethe shutter coil is connected with the output terminal pad by welding,it is possible to protect other components of the camera module fromheat and also prevent the performance deterioration of the image sensorand the like.

While the present invention has been described with respect to thespecific embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

The invention claimed is:
 1. A camera module comprising: a substrate including an electrode pad; an image sensor disposed on the substrate; a housing fixed on the substrate and accommodating a first lens; an actuator disposed on the housing and including an electrode terminal and a second lens; and a conductive pattern having a first end electrically connected to the electrode pad and a second end connected to the electrode terminal, wherein the conductive pattern extends along a surface of the housing from the electrode pad to the electrode terminal, wherein the housing is disposed on an upper surface of the substrate, wherein the conductive pattern includes a bottom conductive pattern disposed on a bottom surface of the housing, and wherein at least a portion of the bottom conductive pattern surface-contacts with the electrode pad disposed on the upper surface of the substrate.
 2. The camera module according to claim 1, wherein the actuator comprises a micro electromechanical system (MEMS) actuator.
 3. The camera module according to claim 1, wherein the electrode pad of the substrate comprises two terminals.
 4. The camera module according to claim 1, wherein the actuator has an opening for fixing the second lens.
 5. The camera module according to claim 1, further comprising: a shutter disposed on the actuator, wherein a shutter coil extended from the shutter is welded to an output terminal pad formed at the substrate.
 6. The camera module according to claim 5, wherein the shutter coil and the output terminal pad are respectively provided in a pair so as to be corresponding to a positive pole and a negative pole.
 7. The camera module according to claim 6, wherein the shutter coil is welded by a welding machine.
 8. A phone having a camera module of claim
 1. 9. The camera module according to claim 1, wherein the bottom conductive pattern and the electrode pad are contacted by a conductive adhesive.
 10. A camera module comprising: a substrate including an electrode pad; an image sensor disposed on the substrate; a housing fixed on the substrate and accommodating a first lens; an actuator disposed on the housing and including an electrode terminal and a second lens; and a conductive pattern having a first end electrically connected to the electrode pad and a second end connected to the electrode terminal, wherein the conductive pattern extends along a surface of the housing from the electrode pad to the electrode terminal, wherein the housing comprises a holder disposed on the substrate and a lens barrel comprising the first lens, the lens barrel being coupled to the holder, the conductive pattern comprises a first pattern and a second pattern, and the first pattern is formed on an inner surface of the holder and the second pattern is formed on an outer surface of the lens barrel.
 11. The camera module according to claim 10, wherein said first end of the conductive pattern is one end of the first pattern and said second end of the conductive pattern is one end of the second pattern.
 12. The camera module according to claim 10, wherein an extended portion is formed at an upper end of the lens barrel so as to be contacted with the electrode terminal of the actuator, and the second pattern is extended to an upper surface of the extended portion.
 13. The camera module according to claim 10, wherein the one end of the first pattern is bonded to the electrode pad by a conductive adhesive.
 14. The camera module according to claim 10, wherein the one end of the second pattern is bonded to the actuator by a conductive adhesive. 